1. Technical Field
The invention relates generally to gait analysis of animal objects. More particularly, one aspect of the invention is directed to monitoring and characterization of walking and running behaviors under a controlled environment for an animal, for example, a mouse or a rat, using video analysis from a bottom view image, either obtained directly by placing a camera underneath a transparent treaded treadmill or by placing a mirror that reflects the bottom view image onto the side where the camera can capture them. In all cases, a treadmill with a transparent tread or belt is used.
2. Background Art
Animals, for example mice or rats, are used extensively as human models in the research of drug development; genetic functions; toxicology research; understanding and treatment of diseases; and other research applications. Despite the differing lifestyles of humans and animals, for example mice, their extensive genetic and neuroanatomical homologies give rise to a wide variety of behavioral processes that are widely conserved between species. Exploration of these shared brain functions will shed light on fundamental elements of human behavioral regulation. Therefore, many behavioral test experiments have been designed on animals like mice and rats to explore their behaviors. These experiments include, but not limited to, home cage behaviors, open field locomotion experiments, object recognition experiments, a variety of maze experiments, water maze experiments, freezing experiments for conditioned fear, and gait analysis experiments. All these apparatus and experiments use, in many cases, human observation of videotapes of the experiment sessions, resulting in inaccuracy, subjectivity, labor-intensive, and thus expensive experiments.
Of particular interest here are the gait analysis experiments. The purpose of the gait analysis experiments is to enable the scientist to measure various parameters of walking or running behaviors including, but not limited to, stride length, stride speed, time of contact of feet with the floor, spacings between feet, trajectories of the individual feet, etc.
Scientists have two available methods to generate these strides from an animal—1) placing the animal on an art paper with its feet dipped in ink and letting the animal walk on the paper thereby generating footprints in the paper and measuring parameters from these footprints; and 2) placing the animal on a treadmill and manually observing the video and scoring the parameters from the video data. Usually, this treadmill is a conventional animal treadmill with an opaque belt. Hence, the parameter measurements are extremely difficult to determine accurately. In the first case, the footprints are never accurate as artifacts such as blotches, ink drops, or irregular prints can generate unreliable results. In both of these cases, the manual measurement process is a slow, tedious, and highly-subjective process.
Instead of using an opaque belt for the treadmill approach, a transparent belt can be used and the walking animal can be observed through this transparent belt. This introduces the opportunity to utilize the latest technologies in computer vision, image processing, and digital video processing to automate the processes and achieve better results, high throughput screening, and lower costs.